A bone mineral density test is an important test that determines your bone health and lets you know how much calcium and other minerals your bones have. These results tell you if you’re at risk for certain health conditions or fractures. This article will discuss everything you need to know about the test, including what to expect and who needs one.
What is a bone mineral density test?
A bone mineral density test (BMD) measures calcium and other important minerals to determine bone health. A bone mineral density test diagnoses medical conditions like osteopenia and osteoporosis, which increase your risk for bone fractures. Even if you don’t have these conditions, a BMD determines your risk of getting fractures.
Why do you need a bone density test?
Bone mineral density tests are important because if you’re at risk for getting a fracture, you can take precautions to prevent falls or start treatment to strengthen your bone health.
There are a few different reasons to get a bone density test, such as:
- Diagnose osteopenia/osteoporosis
- Determine your risk of bone fracture
- Rate of bone loss
- See if treatment for osteoporosis is working
As we age we lose calcium, and our bones weaken, so your doctor may want you to get a BMD. Bone mineral density tests are recommended for:
- Women over the age of 65
- Men over the age of 70
- Anyone at risk for fractures or osteoporosis
Low bone density affects many people, especially women. There are 10 million people with osteoporosis, and 80 percent are women. One in every two women over 50 will break a bone.
Risk factors for osteoporosis
Some people are at a higher risk of developing osteoporosis. You might be at a higher risk for it if you have:
- Kidney disease
- Rheumatoid arthritis (RA)
- A history of smoking
- A history of eating disorders or low BMI
- Early menopause
- A significant drop in hormone levels
- Previous hip fracture or family history of hip fractures
- History of excessive alcohol use
Certain medications such as long-term steroids can increase your risk for bone fractures. If you’re on any medication that might increase your risk for osteoporosis, talk to your doctor about getting a bone density test.
What to expect during your test
Before you get your bone mineral density test, it’s important to know more about the test to understand how it is given.
Before your test, you’ll get a low dose of radiation, which calculates your bone density, how much calcium, and other important minerals you have in your bones.
After the radiation is given, you’ll lie on an exam table where an X-ray will be positioned under you, and a machine called a detector is above you. The detector will pass over you to get the images your doctor needs, taking images of your hips, spine and any other area your doctor recommends. Your healthcare team may ask you to move to different positions or hold your breath for a few seconds to get the best images possible.
The test is noninvasive and takes about 30 minutes. After the test is complete, the images will be read by a radiologist, a doctor specializing in these tests and interpreting the results.
How to prepare for a bone mineral density test
You’ll want to talk to your doctor about preparing for your bone density test. General instructions usually include:
- Don’t take any calcium supplements 24 hours before the test
- Wear loose, comfortable clothing
- Avoid wearing any metal
- Remove your glasses, any jewelry and removable dental work
- Remove anything that contains metal
You’ll also want to tell your doctors about any joint or metal implants you have. If you’ve recently had a CT scan with contrast or a barium enema, let them know as they may need to reschedule your test.
Understanding Bone Density Test Results
To understand the results of your bone density test, it’s important to know how they measure it. The test has two scores: the T score and the Z score. Here is what they mean.
T score
The T score compares your bone mineral density test results to healthy adults aged 25-35 of the same sex and ethnicity. A positive T score means your bones are stronger than normal and a negative score means the bone is weaker than normal.
Z score
Your Z score compares your results to people of the same age, sex, race and of similar height and weight.
After a doctor determines these risk scores, they can either diagnose a bone health medical condition or let you know how likely you are to get a bone fracture.
Bone mineral density tests are important for many people, especially women. If you’re at risk for osteoporosis or bone fractures, talk to your healthcare provider about a BMD so that you can be proactive about taking care of your bone health.
